Galactic empires are a fairly common theme in science fiction. The idea suffers from practical difficulties, not least that it requires faster-than-light travel (and communication) to hold the empire together. Nonetheless, many authors have either used a galactic empire as background, or written about the growth or decline of such an empire. Some of these empires are clearly based on the Roman empire; that of Isaac Asimov's Foundation series (which inspired galactic empires of later writers and film-makers) being an obvious example. The best known to the general public today is probably the empire from Star Wars, which was formed from the ashes of the Galactic Republic. Frank Herbert'sDune features a universe-spanning empire.
